Sex education in Britain is poorly practised, in schools as well as in the home. British so called ‘Puritanism’ has been seen as one of the reasons. At a time and age when teenage pregnancy, Sexual Transmitted Infections (STIs) and viruses (AIDS/HIV) are on the increase more attention to the education of sexual behaviour is needed. Government initiatives are leading in that direction for schools as well as families, but it is unclear how these are materialised. Especially, how families discuss sexual matters is underresearched and poorly understood. Therefore, the aims of this study were to explore the potential facilitators and barriers of the communication of sexual topics, with and without the use of a Sex and Relationship Education (SRE) multimedia program, and to explore the impact of this program on the knowledge of sexual issues and concerns. A mixed-method design was employed by using Strauss and Corbin’s (1998) modified grounded theory to develop a model reflecting the findings. Knowledge was assessed on data gathered from twenty British families over a ten-month period. Using semi-structured interviews, observational field notes and quantitative measures, it was found that trust, respect, spending (leisure) time together and children’s perception of their parents’ sexual knowledge were facilitators for sexual communications. Older siblings and other family members who were regarded as role models also facilitated the discussion of sexual matters. The barriers for discussing sexual issues openly within families included authoritative parenting, lack of parental sexual knowledge, presence of younger siblings and parents’ direct questioning of children’s personal relationships. In light of this, the multimedia program could be beneficial in many more families when initiating and communicating sexual matters.